<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- This file documents the use of the GNU compilers.

Copyright (C) 1988-2023 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Funding Free Software", the Front-Cover
Texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below).  A copy of the license is included in the section entitled
"GNU Free Documentation License".

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU
     software.  Copies published by the Free Software Foundation raise
     funds for GNU development. -->
<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Deprecated Features (Using the GNU Compiler Collection (GCC))</title>

<meta name="description" content="Deprecated Features (Using the GNU Compiler Collection (GCC))">
<meta name="keywords" content="Deprecated Features (Using the GNU Compiler Collection (GCC))">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html#Top" rel="start" title="Top">
<link href="Indices.html#Indices" rel="index" title="Indices">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="C_002b_002b-Extensions.html#C_002b_002b-Extensions" rel="up" title="C++ Extensions">
<link href="Backwards-Compatibility.html#Backwards-Compatibility" rel="next" title="Backwards Compatibility">
<link href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" rel="prev" title="C++ Concepts">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smalllisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>


</head>

<body lang="en_US">
<a name="Deprecated-Features"></a>
<div class="header">
<p>
Next: <a href="Backwards-Compatibility.html#Backwards-Compatibility" accesskey="n" rel="next">Backwards Compatibility</a>, Previous: <a href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" accesskey="p" rel="prev">C++ Concepts</a>, Up: <a href="C_002b_002b-Extensions.html#C_002b_002b-Extensions" accesskey="u" rel="up">C++ Extensions</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Deprecated-Features-1"></a>
<h3 class="section">7.11 Deprecated Features</h3>

<p>In the past, the GNU C++ compiler was extended to experiment with new
features, at a time when the C++ language was still evolving.  Now that
the C++ standard is complete, some of those features are superseded by
superior alternatives.  Using the old features might cause a warning in
some cases that the feature will be dropped in the future.  In other
cases, the feature might be gone already.
</p>
<p>G++ allows a virtual function returning &lsquo;<samp>void *</samp>&rsquo; to be overridden
by one returning a different pointer type.  This extension to the
covariant return type rules is now deprecated and will be removed from a
future version.
</p>
<p>The use of default arguments in function pointers, function typedefs
and other places where they are not permitted by the standard is
deprecated and will be removed from a future version of G++.
</p>
<p>G++ allows floating-point literals to appear in integral constant expressions,
e.g. &lsquo;<samp> enum E { e = int(2.2 * 3.7) } </samp>&rsquo;
This extension is deprecated and will be removed from a future version.
</p>
<p>G++ allows static data members of const floating-point type to be declared
with an initializer in a class definition. The standard only allows
initializers for static members of const integral types and const
enumeration types so this extension has been deprecated and will be removed
from a future version.
</p>
<p>G++ allows attributes to follow a parenthesized direct initializer,
e.g. &lsquo;<samp> int f (0) __attribute__ ((something)); </samp>&rsquo; This extension
has been ignored since G++ 3.3 and is deprecated.
</p>
<p>G++ allows anonymous structs and unions to have members that are not
public non-static data members (i.e. fields).  These extensions are
deprecated.
</p>
<hr>
<div class="header">
<p>
Next: <a href="Backwards-Compatibility.html#Backwards-Compatibility" accesskey="n" rel="next">Backwards Compatibility</a>, Previous: <a href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" accesskey="p" rel="prev">C++ Concepts</a>, Up: <a href="C_002b_002b-Extensions.html#C_002b_002b-Extensions" accesskey="u" rel="up">C++ Extensions</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p>
</div>



</body>
</html>
